Irrigation system with freeze protection and method

ABSTRACT

Apparatus and method are provided herein for causing and controlling the injection of antifreeze material into a water line of an irrigation system. The irrigation system comprises an antifreeze supply unit including an antifreeze storage container containing a liquid antifreeze coupled to a water line of the irrigation system. A control unit is coupled to the antifreeze supply unit. The control unit is configured to cause the antifreeze supply unit to inject at least some of the liquid antifreeze from the antifreeze storage container into the water line. The control unit can cause the antifreeze supply unit to inject the liquid antifreeze from the antifreeze storage container in response to temperature data received from a sensor unit or in response to user input at the control unit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to irrigation and, in particular, to asystem and method for controlling irrigation systems to prevent freezingin irrigation systems and components.

2. Discussion of the Related Art

It is known to shut down irrigation systems during the colder months toprevent the freezing of water within the main supply and lateral linesfor prevention of damage to such lines. During the fall season, it iscommon to employ local irrigation contractors to evacuate water fromtheir underground irrigation systems in an effort to prevent the waterlines from freezing. Typically, before an irrigation system is shutdown, an operator has to manually drain or forcibly purge the water fromthe irrigation system. Similarly, when warmer months arrive, thecontractor has to return to the irrigation system site to energize theirrigation system.

This process, more commonly referred to as winter shut down orwinterization, can be a source of frustration for home and businessowners in trying to schedule the service at the most optimal time aswell as the possibility of system damage at the time of service ordiscovering it in the spring when the system is energized. For example,forced air evacuations of automatic irrigation systems are sometimesperformed at dangerously high pressures and flow rates and can result inimmediate as well as long-term system damage to critical irrigationcomponents, i.e. valves, vacuum breakers, spray heads, rotors and pipeconnections. Further, if damage of this nature is not discovered at thetime of spring start-up, significant collateral damage can result,including, but not limited to, erosion, seed washout, sink holeformation, property flooding and plant species termination.

Known irrigation equipment freeze protection systems either conduct atemperature threshold-induced automatic shutdown and draining of themain line of the system, hot water injection into the main and lateralzones, or a continual weeping of main line water until a full systemmanual shutdown can be performed. Such systems can activateautomatically based on input from air and/or water temperature sensors.In addition, systems that rely on temperature sensors may respond to anunusual single day drop in temperature and prematurely activate thewinterization system for the entire winter prior to the actual arrivalof colder temperatures.

SUMMARY OF THE INVENTION

Several embodiments of the invention provide methods and apparatus forwinterization of an irrigation system to prevent freezing during thecolder months.

In one embodiment, an irrigation system comprises: an antifreeze supplyunit coupled to a water line of the irrigation system, the antifreezesupply unit including a storage container containing a liquidantifreeze; and a control unit in communication with the antifreezesupply unit, the control unit being configured to send a signal to theantifreeze supply unit and the antifreeze supply unit being configuredto inject at least some of the liquid antifreeze from the antifreezestorage container into the water line in response to receiving thesignal from the control unit.

In another embodiment, a control unit for controlling an irrigationsystem comprises: a memory storing temperature thresholds of at leastone of air and water temperatures associated with a geographicallocation of the irrigation system, the memory including at least a lowertemperature threshold; an output configured to be in communication withan antifreeze supply unit including an antifreeze storage containercoupled to a water line of the irrigation system; and a processorcoupled to the memory and the output; wherein the processor isconfigured to generate a signal at the output upon a determination bythe processor that at least one of air and water temperature approachesthe lower temperature threshold, the signal being configured to causethe antifreeze supply unit to inject at least some of the liquidantifreeze from the antifreeze storage container into the water line.

In yet another embodiment, a method for controlling an irrigation systemcomprises: outputting a signal from a control unit of an irrigationsystem comprising a water line and an antifreeze supply unit coupled tothe water line and including an antifreeze storage container containinga liquid antifreeze, wherein the control unit comprises a processor andmemory containing instructions executable by the processor; receivingthe signal at the antifreeze supply unit; and injecting, responsive tothe signal received at the antifreeze supply unit, at least some of theliquid antifreeze from the antifreeze storage container of theantifreeze supply unit into the water line.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of severalembodiments of the present invention will be more apparent from thefollowing more particular description thereof, presented in conjunctionwith the following drawings.

FIG. 1 is a diagram of an irrigation system including a winterizationcontrol unit according to one embodiment;

FIG. 2 is a functional diagram of a winterization control unit accordingto one embodiment;

FIG. 3 is a functional diagram of a winterization control unit accordingto another embodiment;

FIG. 4 is a functional diagram of the winterization control unit of FIG.3 being connected to an exemplary main irrigation controller accordingto some embodiments;

FIG. 5 is a functional diagram of a winterization control unit accordingto another embodiment, where the winterization control unit isincorporated into the physical structure of an exemplary main irrigationcontroller;

FIG. 6 is a functional diagram of a winterization control unit accordingto another embodiment, where the winterization control unit is removablymounted as a module onto an exemplary modular main irrigationcontroller;

FIG. 7 is a perspective view in partial cross section of an antifreezesupply/storage unit according to one embodiment, showing the structureof a pump and an antifreeze storage container housed within theantifreeze supply/storage unit;

FIG. 8 depicts a flow diagram of an exemplary winterization controlprocess according to one embodiment for use with various winterizationcontrol systems;

FIG. 9 depicts a flow diagram of an exemplary winterization controlprocess according to one embodiment for use with various winterizationcontrol systems;

FIG. 10 depicts a flow diagram of an exemplary winterization controlprocess according to one embodiment for use with various winterizationcontrol systems; and

FIG. 11 depicts a flow diagram illustrating an exemplary method forcontrolling an irrigation system according to one embodiment for usewith various winterization control systems.

Corresponding reference characters indicate corresponding componentsthroughout the several views of the drawings. Skilled artisans willappreciate that elements in the figures are illustrated for simplicityand clarity and have not necessarily been drawn to scale. For example,the dimensions of some of the elements in the figures may be exaggeratedrelative to other elements to help to improve understanding of variousembodiments of the present invention. Also, common but well-understoodelements that are useful or necessary in a commercially feasibleembodiment are often not depicted in order to facilitate a lessobstructed view of these various embodiments of the present invention.

DETAILED DESCRIPTION

The following description is not to be taken in a limiting sense, but ismade merely for the purpose of describing the general principles ofexemplary embodiments. The scope of the invention should be determinedwith reference to any claims supported by this specification.

Reference throughout this specification to “one embodiment,” “anembodiment,” “some embodiments” or similar language means that aparticular feature, structure, or characteristic described in connectionwith the embodiment/s is included in at least one embodiment of thepresent invention. Thus, appearances of the phrases “in one embodiment,”“in an embodiment,” “some embodiments” and similar language throughoutthis specification may, but do not necessarily, all refer to the sameembodiment(s).

Furthermore, the described features, structures, or characteristics ofthe invention may be combined in any suitable manner in one or moreembodiments. In the following description, numerous specific details areprovided to provide a thorough understanding of embodiments of theinvention. One skilled in the relevant art will recognize, however, thatthe invention can be practiced without one or more of the specificdetails, or with other methods, components, materials, and so forth. Inother instances, well-known structures, materials, or operations are notshown or described in detail to avoid obscuring aspects of theinvention.

Referring to FIG. 1, one embodiment of an irrigation system 10 is shown.The system 10 includes a main irrigation controller 12 coupled to awinterization control unit 14 via a communication line 11. In FIG. 1,the winterization control unit 14 is shown as having only a processor 16(for example, a microprocessor or a microcontroller) and a memory 20,and the main irrigation controller 12 is shown as having only aprocessor 13 and a memory 17 for illustration purposes only. FIGS. 2-5provide a more detailed depiction of the interior components of severalexemplary winterization control units and main irrigation controllers.The main irrigation controller 12 is programmed to execute one or morewatering schedules.

Water to the system 10 is supplied from a main water supply 18 and flowsvia a master or gate valve 19 through a main water line 15, a pluralityof lateral water lines 22 a, 22 b, and 22 c, and a plurality of zonevalves 24 a, 24 b, and 24 c (under control by the irrigation controller12) to a plurality of sprinklers 25 a, 25 b, and 25 c. It will beappreciated that while three water lines 22 a, 22 b, and 22 c havingbeen shown as branches of the main water line 15, the system 10 caninclude any number of lateral water lines branching from the main waterline 15. As discussed in more detail below in reference to theembodiment of FIG. 7, liquid antifreeze is supplied to the main waterline 15 from an antifreeze supply/storage unit 100, described in moredetail below, which is configured to receive signals from thewinterization control unit 14 and initiate the injection of liquidantifreeze 105 from an antifreeze storage container 104 through anantifreeze supply unit 100 into the main water line 15. Generally, theliquid antifreeze 105 may be embodied as a liquid antifreeze concentrateor a liquid antifreeze solution including a ratio of liquid antifreezeand a base solvent, such as water. It is understood that the ratio ofliquid antifreeze to such base solvent embodied as a solution may bevariable and dependent on the application.

The main irrigation controller 12, which controls water flow in the mainline 15 and the lateral zones 22 a, 22 b, and 22 c of the irrigationsystem 10 during the normal irrigation operation of the system 10, isconfigured to output activation signals (e.g., 24 volt A/C powersignals) to respective ones of a plurality of lateral activation linesdepicted by the dashed lines 21 a, 21 b, and 21 c, each coupled to arespective zone valve 24 a, 24 b, and 24 c located in a region to beirrigated. The presence of an activation signal on a given activationline 21 a, 21 b, 21 c causes the opening of the respective zone valve 24a, 24 b, 24 c, and the absence of such activation signal results in theclosing of the zone valve. As is well known, each zone valve 24 a, 24 b,and 24 c controls water flow to one or more sprinkler devices 25 a, 25b, and 25 c, drip lines and/or other irrigation devices that may becoupled to each valve 24 a, 24 b, and 24 c. Typically, the wateringdevices (e.g., 25 a, 25 b, and 25 c) coupled to a given zone valve 24 a,24 b, and 24 c define a watering zone.

While the main irrigation controller 12 is shown in FIG. 1 as beingcoupled to the water line 15 via the winterization control unit 14, itis to be appreciated that the main irrigation controller 12 may bedirectly coupled to the water line 15. It is also appreciated that theopening and closing of the zone valves 24 a, 24 b, and 24 c may becontrolled via control units coupled to each zone valve that demodulatedata from modulated power signals sent over a shared Z-wire path (e.g.,2 or 3 wire control path) to all valves 24 a, 24 b, and 24 c.

In an embodiment depicted in FIG. 2, the winterization control unit 114can include a processor 116 electrically coupled to a power supply 118and a memory 120. The processor 116 can also be electrically coupled toan input 122 that can receive signals from the main irrigationcontroller 12 or from any other source, for example, a central stationor central controller (not shown) through which the winterizationcontrol unit 114 can be remotely controlled. The processor 116 can alsobe electrically coupled to an output 124, which can be in communicationwith any number of devices, for example, one or more valves, waterlines, and antifreeze containers, as discussed below.

In another embodiment, the winterization control unit 214 can include aprocessor 216 electrically coupled to a power supply 218 and a memory220, as shown in FIG. 3. The processor 116 can also be electricallycoupled to a sensor input 222 that can receive signals from a pluralityof sensors 226, i.e., air temperature sensors, water temperaturesensors, ground temperature sensors, and/or pressure sensors. Thewinterization control unit 214 can also receive signals at input/output224 from the main irrigation controller 12 or from any other source, forexample, a central station or central controller (not shown) that canremotely control the winterization control unit 214. The winterizationcontrol unit 214 can also send signals (e.g., commands) from itsinput/output 224 to various devices in communication with thewinterization control unit 14, for example, the main irrigationcontroller 12, the antifreeze supply unit 100, the control valve 40, andthe pressure reducing valve 48. The winterization control unit 214 caninclude a control panel 228 providing a user interface through which auser can manually control the winterization control unit 214 while beingpresent at the physical location of the winterization control unit 214.The control panel 228 can include various buttons or touch screen inputs230 that permit the user to manually input various commands for thewinterization control unit 214 to execute. The control panel 228 canalso include an electronic display 232 that permits the user to seevarious menus and options displayed by the winterization control unit214.

As discussed in more detail below, the winterization control units 14,114, and 214 can be coupled to the main irrigation controller 12directly via a wired or wireless connection or an interface.Alternatively, the winterization control units 14, 114, and 214 can beimplemented as a part of the main irrigation controller 12. For example,any one of the winterization control units 14, 114, and 214 may beimplemented as a module that is configured to be inserted into a modularmain irrigation controller.

FIG. 4 illustrates an exemplary embodiment where the winterizationcontrol unit 214 is physically separate from and electrically coupled(via connection 250) to an exemplary main irrigation controller 212. Themain irrigation controller 212 includes a controller 213 (for example, amicrocontroller or a control system) that typically includes one or moreprocessors (such as one or more microprocessors). The controller 213 canbe electrically coupled to a power supply 215, a memory 217, a userinterface 219, and an output 221. The connection 250 can be in the formof a power line, cable, or a wireless communication channel.

In the embodiment illustrated in FIG. 4, the input/output 224 of thewinterization control unit 214 is in communication via a connection 234with an optional main power control switch 236, which in turn is incommunication via a connection 238 with the input/output 221 of the mainirrigation controller 212. At appropriate times, as discussed in moredetail below, in response to receiving a signal from the winterizationcontrol unit 214, the main power control switch 236 is configured toeither shut off electrical power or to provide electrical power to themain irrigation controller 212. It is to be appreciated that such asignal can be generated by the processor 216 of the winterizationcontrol unit 214 either in response to an input such as a commandentered manually by a user via the user interface 228, or a commandinput initiated at a central station or a central controller remote tothe winterization control unit 214.

In another embodiment illustrated in FIG. 5, the winterization controlunit 314 is implemented into, and forms a part of, the physicalstructure of the main irrigation controller 312. As shown in FIG. 5, thewinterization control unit 314 is identical to the winterization controlunit 214 of FIG. 4, except that it does not have its own power supply(like the power supply 218). Instead, the processor 316 of thewinterization control unit 314 is electrically coupled to a power supply315 of the main irrigation controller 312. It is to be appreciated,however, that the winterization control unit 314 can also include itsown power supply such that the processor 316 could be coupled to thepower supply 315 of the main irrigation controller 312, the power supplyof the winterization control unit 314 (now shown), or both. In theembodiment illustrated in FIG. 5, the main irrigation controller 312includes a controller 313 (for example, a microcontroller or a controlsystem) having one or more processors (for example, one or moremicroprocessors), a power supply 315, a memory 317, and an input/output221 for communicating with external devices.

While the winterization control unit 314 and the main irrigationcontroller 312 have been illustrated in FIG. 5 as each having their ownprocessor and memory, it is to be appreciated that the winterizationcontrol unit 314 may be configured without the memory 320 such that itutilizes the memory 317 of the main irrigation controller 312.Similarly, it is to be appreciated that the winterization control unit314 may be configured without the processor 316 such that it utilizesthe controller 313 of the main irrigation controller 312, which may beprogrammed to execute all of the winterization functions of theprocessor 316. As shown in FIG. 5, the processor 316 is electricallycoupled to a sensor input 322 that can receive signals from a pluralityof sensors, i.e., air temperature sensors, water temperature sensors,ground temperature sensors, and/or pressure sensors. While the sensorinput location 322 has been depicted in FIG. 5 as being a part of thewinterization control unit 314, the winterization control unit 314 canbe configured without the sensor input location 322 such that itutilizes a sensor input location (not shown) implemented into thestructure of the main irrigation controller 312.

In the embodiment illustrated in FIG. 5, the input/output 324 of thewinterization control unit 314 is in communication via an electricalconnection 334 with the controller 313 of the main irrigation controller312. At appropriate times, as discussed in more detail below, theprocessor 316 of the winterization control unit 314 is configured tosend one or more signals via the connection 334 to the controller 313 ofthe main irrigation controller 312. It is to be appreciated that suchsignals can be generated by the processor 316 in response to an inputsuch as a command entered manually by a user via the user interface 328and/or a command initiated at a central station remote to thewinterization control unit 314.

FIG. 6 illustrates another exemplary embodiment where a winterizationcontrol unit 414 is a module that can be removably mounted onto the mainirrigation controller 412. In this form, the main irrigation controller412 is a modular irrigation controller and includes a controller 413(for example, a microcontroller or a control system) including one ormore processors (for example, one or more microprocessor), a powersupply 415, a memory 417, a user interface 419, and an input/output 421.The main irrigation controller 412 further includes at least one modulemounting location 440 configured to accommodate the docking andelectrical coupling of the winterization control unit 414 and/or othertraditional expansion station modules. To that end, the winterizationcontrol unit 414 includes a connector 442 configured to mate with themodule mounting location 440 to mount the winterization control unit 414to the main irrigation controller 412.

The connector 442 can include pins that carry power and data signalsfrom the winterization control unit 414 to the main irrigationcontroller 412. While one module mounting location 440 has been shown inFIG. 6, it is to be appreciated that the main irrigation controller 412may include a plurality of module mounting locations 440. The modulemounting location 440 may be accessible from the exterior of the mainirrigation controller 412 housing, or may be located in the interior ofthe main irrigation controller 412 housing such that the mounting of thewinterization control unit 414 to the main irrigation controller 412would require removal of one or more panels on, or partial disassemblyof, the main irrigation controller 412.

The connector 442 permits the processor 416 of the winterization controlunit 414 to send signals to and/or receive signals from the controller413 (for example, a microcontroller or control system) of the mainirrigation controller 412. For example, the processor 416 of thewinterization control unit 414 can send a signal via an electricalconnection 437 through the connector 442 and the module mountinglocation 440 to the controller 413 of the main irrigation controller 412to either shut off electrical power, or to provide electrical power tothe main irrigation controller 412. It is to be appreciated that such asignal can be generated by the processor 416 in response to an inputsuch as a command entered manually by a user via the user interface 428and/or an input such as a command initiated at a central station or acentral controller remote to the winterization control unit module 414.

While the winterization control unit 414 and the main irrigationcontroller 412 have been illustrated in FIG. 6 as each having their ownprocessor and memory, it is to be appreciated that the winterizationcontrol unit 414 may be configured without the memory 420 such that itutilizes the memory 417 of the main irrigation controller 412.Similarly, it is to be appreciated that the winterization control unit314 may be configured without the processor 416 such that it utilizesthe controller 413 of the main irrigation controller 412, which may beprogrammed to execute all of the winterization functions of theprocessor 416.

In the embodiment depicted in FIG. 6, the processor 416 of thewinterization control unit 414 is electrically coupled to an output 424.The winterization control unit 414 can output signals to, for example,the antifreeze supply unit 100, via the input/output 421 of the mainirrigation controller, or via the output 424. As shown in FIG. 6, theprocessor 416 is also electrically coupled to a sensor input 422 thatcan receive signals from a plurality of sensors, i.e., air temperaturesensors, water temperature sensors, ground temperature sensors, and/orpressure sensors. While the sensor input location 422 has been depictedin FIG. 6 as being a part of the winterization control unit 414, thewinterization control unit 414 can be configured without the sensorinput location 422 such that it utilizes a sensor input location (notshown) implemented into the structure of the main irrigation controller412. When so configured, the controller 413 of the main irrigationcontroller 412 can send a signal (including, for example, air and/orwater temperature reading data) via the electrical connection 437through the connector 442 and the module mounting location 440 to theprocessor 416 of the winterization control unit 414.

In the embodiment illustrated in FIG. 1, the winterization control unit14 has a pressure input via a connection 26 from a pressure sensor 28coupled to the main water line 15. It will be appreciated that theconnection 26 can be wired or wireless. In one approach, the pressuresensor 28 includes circuitry and a transmitter configured to sendsignals to the winterization control unit 14. The pressure sensor 28 canbe programmed to perform pressure measurements at predeterminedintervals, or continuously, and to send signals including pressuremeasurement data at predetermined intervals, or in real-time, to thewinterization control unit 14.

As shown in FIG. 1, the winterization control unit 14 also has an airtemperature input via a connection 30 from an air temperature sensor 32.It will be appreciated that the connection 30 can be wired or wirelesscommunication and that the air temperature sensor 32 can be above-groundor subterranean, and can be configured to measure ground temperatureand/or ambient air temperature. In one approach, the air temperaturesensor 32 includes circuitry and a transmitter configured to sendsignals to the winterization control unit 14. The air temperature sensor32 can be programmed to perform air temperature measurements atpredetermined intervals or continuously, and to send signals includingair temperature measurement data at predetermined intervals, or inreal-time, to the winterization control unit 14.

The winterization control unit 14 also has a water temperature input viaa connection 34 from a water temperature sensor 36 coupled to the mainwater line 20. It will be appreciated that the connection 34 can bewired or wireless. The water temperature sensor 36 can be coupled to themain water line 15 to measure the fluid (e.g., water, or a mixture ofwater and liquid antifreeze 105) temperature in the main water line 15.In one approach, the water temperature sensor 36 includes circuitry anda transmitter configured to send signals to the winterization controlunit 14. The water temperature sensor 36 can be programmed to performwater temperature measurements at predetermined intervals orcontinuously, and to send signals including water temperaturemeasurement data at predetermined intervals, or in real time, to thewinterization control unit 14.

With reference to FIG. 1, the winterization control unit 14 also has anoutput (not shown in FIG. 1, but shown, for example, in FIGS. 2-5)connected via a connection 38 to a control valve 40. It is to beappreciated that the connection 38 can be wired or wireless. The controlvalve 40 is configured for controlling the fluid source for the mainwater line 15 of the irrigation system 10, such that in some cases,regardless of whether the gate valve 19 is open or closed, the controlvalve 40 can maintain the shut-off of the water supply 18 into the mainwater line 15, for example, during the winterization cycle, as describedin more detail below. The control valve 40 can be a 3-way control valvethat is adapted, in addition to receiving signals (e.g., commands) fromthe winterization control unit 14, to shut-off the main water supply 18through the main water line 15, to introduce antifreeze from theantifreeze supply unit 100 into the main water line 15 via a connection44, and to permit the flow of water from the main water supply 18through the gate valve 19 and into the main water line 15, as will bediscussed in more detail below.

Downstream of the control valve 40, the system 10 can include a flowsensor 41 coupled to the main water line 15 and in communication withthe winterization control unit 14 via a connection 43, which can be awired or a wireless connection. In one approach, the flow sensor 41includes circuitry and a transmitter configured to send signals to thewinterization control unit 14, as discussed in more detail below.

As shown in FIG. 1, the winterization control unit 14 is programmed tosend signals in the form of commands directly to an antifreeze supplyunit 100 via a connection 54, which can be a wired or wirelessconnection. As discussed in more detail below, in response to receivinga signal (e.g., an electrical power signal or a data signal) from thewinterization control unit 14, the antifreeze supply unit 100 can causea liquid antifreeze to be introduced via the connection 44 into the mainwater line 15, in one approach, via a one-way injection port 46.Optionally, the one-way injection port 46 can include a check valve (notshown).

With further reference to FIG. 1, a pressure reducing valve 48 iscoupled via a connection 50 to the main water line 15 and via aconnection 52 to the connection 44 through which the antifreeze isinjected into the main water line 15. In one approach, the pressurereducing valve 48 is configured to provide reduced main line 15 waterpressure to control the flow rate of a liquid antifreeze 105 from theantifreeze supply unit 100 into the main water line 15.

FIG. 7 depicts an exemplary antifreeze supply unit 100 usable with theirrigation system 10. For purposes of this application, an “antifreezesupply unit” will be understood as a structure which, alone, or whencoupled to other structures, receives a signal from the winterizationcontrol unit 14 and causes the liquid antifreeze 105 to be injected intothe main water line 15 of the irrigation system 10. In some embodiments,the antifreeze supply unit 100 includes, or is coupled to, an electricalinput and/or logic circuitry configured to receive a power signal and/ordata signal from the winterization control unit 14. In some embodiments,the antifreeze supply unit 100 can include a simply valve or otherstructure that opens and closes based on receiving a power signal fromthe winterization control unit 14. In some embodiments, the antifreezesupply unit 100 also includes, or is coupled to, a structure configuredto store a liquid antifreeze 105.

In the illustrated embodiment, the antifreeze supply unit 100 includes ahousing 102 and an antifreeze storage container 104 positioned at leastin part within the housing 102. It is to be appreciated that theantifreeze storage container 104 can be located entirely within thehousing 102, partly within the housing 102, or entirely outside of thehousing 102. For example, the antifreeze storage container 104 may bephysically separate from the housing 102 of the antifreeze supply unit100 and connected by one or more pipes to the housing 102 of theantifreeze supply unit 100. In one approach, the housing 102 of theantifreeze supply unit 100 is a valve box. The antifreeze storagecontainer 104 may have a capacity of between about 5 gallons to about 10gallons and can include a spout 108 with a removable cap 110 that allowsa user such as a homeowner or a contractor to easily replenish the levelof the liquid antifreeze 105 in the antifreeze storage container 104.Conversely, the spout 108 can be used to drain the antifreeze storagecontainer 104, if necessary. Preferably, the liquid antifreeze 105 isnon-toxic, biodegradable, and environmentally safe.

In one approach, the liquid antifreeze 105 is a relatively pure mixtureincluding food-grade propylene glycol. Propylene glycol is a generallyclear, odorless, tasteless, non-volatile, viscous liquid with a meltingpoint of −59° C. and a boiling point of 188.2° C. Propylene glycol is ina class of compounds known as organic alcohols. It has a relatively lowvapor pressure and is thus non-volatile in nature. Similar to a morewell-known antifreeze, ethylene glycol, which is commonly used inautomotive coolant applications, propylene glycol is extremely misciblewith water. In one approach the liquid antifreeze 105 can include acolor dye to add color and distinguish the liquid antifreeze 105 frompure propylene glycol (which is colorless) to visibly indicate that theliquid antifreeze 105 is not meant for human consumption. It is to beappreciated that instead of propylene glycol, the liquid antifreeze 105can include other suitable compounds, for example, methanol, ethanol,sodium chloride solution, or polyethylene glycol, or the like, ormixtures thereof.

With further reference to the embodiment of FIG. 7, the antifreezesupply unit 100 includes a pump 106 positioned at least in part withinthe housing 102. It is to be appreciated that the pump 106 can belocated entirely within the housing 102, partly within the housing 102,or entirely outside of the housing 102. In one form, the pump 106 is achemical metering pump, in another form, a variable speed chemicalmetering pump. It is to be appreciated that instead of a metering pump,the pump 106 can be any other suitable pump or pressurized sourcecapable of causing the liquid antifreeze 105 in the antifreeze storagecontainer 104 to be injected into the main water line 15. In one aspectdepicted in FIG. 7, the pump 106 is connected to the antifreeze storagecontainer 104 via a delivery line 107. It is to be appreciated that thepump 106 can be connected to the antifreeze storage container 104 inother ways, for example, the pump 106 can be integrally formed with theantifreeze storage container 104. The pump 106 of the antifreeze supplyunit 100 further includes a second delivery line 109 which can beconnected, for example, via the inlet port 46 shown in FIG. 1, to themain water line 15 in order to deliver the liquid antifreeze 105 to themain water line 15.

In one approach, the pump 106 of the antifreeze supply unit 100 includesinternal logic circuitry and a processor configured to receive powerand/or data signals from any one of the winterization control units 14,114, 214, 314, and 414, and, in response to the received signals, tocause the liquid antifreeze 105 to be injected from the antifreezestorage container 104 into the main water line 15. In another approach,the antifreeze supply unit 100 can include an input, implemented into,or electrically coupled to the pump 106, that can receive an electricalsignal (e.g., an A/C power signal) from the winterization control unit14 that would cause the pump 106 to inject the liquid antifreeze 105into the main line 15. In yet another approach, the antifreeze supplyunit can be configured such that it lacks the pump 106, and theantifreeze storage container 104 is a pressurized container configuredto, upon the opening of a valve, to deliver the liquid antifreeze 105 tothe main water line 15.

In one approach, the processors 16, 116, 216, 316, and 416 of thewinterization control units 14, 114, 214, 314, and 414 are programmed toanalyze trends in data received from the air temperature sensor 32 andthe water temperature sensor 36. To that end, the memory 20, 120, 220,320, and 420 of each winterization control unit 14, 114, 214, 314, and414 can include stored historical values and trends of air temperatures,water temperatures, and ground temperatures associated with thegeographical location (for example, based on zip code) where theirrigation system 10 is located. In addition, the memory 20, 120, 220,320, and 420 of each winterization control unit 14, 114, 214, 314, and414 can include predetermined minimum and maximum temperaturethresholds, which, when approached, would trigger the winterizationcontrol units 14, 114, 214, 314, and 414 to initiate the winterizationcycle, as described in more detail below. In one approach, theprocessors 16, 116, 216, 316, and 416 of the winterization control units14, 114, 214, 314, and 414 are programmed to analyze the air temperaturereadings received from the sensors 32 and 36 over a predetermined timeinterval (for example twice daily, once daily, every other day, onceevery two days, once a week, or any other suitable interval). Thisanalysis is performed in view of the air and water temperaturehistorical trend values to predict whether the air and/or watertemperature trend is approaching the predetermined maximum or minimumtemperature threshold stored in the memory 20, 120, 220, 320, and 420 ofthe winterization control units 14, 114, 214, 314, and 414.

The winterization control units 14, 114, 214, 314, and 414, in additionto being programmed to measure and respond to trends in temperature, canhave specific calendar dates stored in their memories 20, 120, 220, 320,and 420. The specific calendar days (when reached) can cause thewinterization control units 14, 114, 214, 314, and 414 to eitherinitiate the winterization cycle, or to exit the winterization cycle andreturn to normal operation of the irrigation system 10. For exampleonly, the winterization control units 14, 114, 214, 314, and 414 can beprogrammed with a date of November 1, November 15, or December 1, onwhich, regardless of the temperature trends determined based ontemperature sensor input, the winterization control units 14, 114, 214,314, and 414 would begin the winterization cycle. Similarly, thewinterization control units 14, 114, 214, 314, and 414 can be programmedwith a calendar date of February 15, March 1, or March 15, on which,regardless of the temperature trends, the winterization control units14, 114, 214, 314, and 414 would begin to exit from the winterizationcycle and return to the normal irrigation operation of the system 10. Insome embodiments, these calendar dates may be stored as a result ofmanual user input to the winterization control unit. In addition, thewinterization control units 14, 114, 214, 314, and 414 can be programmedsuch that a user such a homeowner or contractor user can override thestored temperature trends and calendar dates by and initiate or exitfrom the winterization cycle by a manual input. In differentembodiments, this manual input from the user can be directly provided atthe physical location of the winterization control units 14, 114, 214,314, and 414, or remotely, for example, from a central station or amobile hand-held unit. In one approach, to enable reception of remoteuser inputs, the winterization control units 14, 114, 214, 314, and 414include a network card and/or a wireless receiver adapted to receiveuser input from a remote internet server via a wired or wireless (e.g.,satellite or cellular) connection.

During the colder months when air temperature typically begins anegative trend, and the processors 16, 116, 216, 316, and 416 of thewinterization control units 14, 114, 214, 314, and 414 determine, forexample, that the air temperature data received over a predeterminedtime period from the air temperature sensor 32 indicates a predictabletrend that the air temperature will go below the low temperaturethreshold stored in the memory 20, 120, 220, 320, and 420 within apredetermined period of time (for example, three days, one week, 10days, etc.), the processors 16, 116, 216, 316, and 416 are programmed toinitiate a winterization cycle, which is described in more detail below.In one approach, the winterization control units 14, 114, 214, 314, and414 can include a visual indicator or an audible alarm that indicates toa user such as a homeowner or a contractor that the winterization cycleis about to begin or has begun. In one approach, the visual indicator oraudible alarm can optionally indicate to the user that the water supply18 to the main water line 15 has been shut off.

Generally, during the winterization cycle of the exemplary system 10depicted in FIG. 1, the winterization control unit 14 sends data and/orpower signals to the antifreeze supply unit 100 to activate the supplyof the liquid antifreeze 105 into the main water line 15 and subsequentlateral lines 22 a, 22 b, and 22 c. When the antifreeze supply unit 100depicted in FIG. 7 receives the signals from the winterization controlunit 14, the pump 106 of the antifreeze supply unit 100 becomesactivated and causes the injection of liquid antifreeze 105 from theantifreeze storage container 104 into the main water line 15 through theinlet port 46 and via the connection 44. When the liquid antifreeze 105fills the main water line 15 and lateral lines 22 a, 22 b, and 22 c(detectable by flow rate/line length calculation or a change in pressurefrom a change in fluid density being emitted from spray heads), the pump106 of the antifreeze supply unit 100 can be deactivated to stop theinjection of the liquid antifreeze 105 into the irrigation system 10.For example, when the desired concentration of the liquid antifreeze 105is reached, a signal (e.g., a power signal or a data signal) can be sentfrom the winterization control unit 14 to the antifreeze supply unit 100to deactivate the pump 106. In one approach, when a predetermineddesirable pressure in the system 10 is achieved, a signal (e.g., a powersignal or a data signal) can be sent from a sensor (e.g., the pressuresensor 28) coupled to the main water line 15 directly to the antifreezesupply unit 100 to deactivate the pump 106. The winterization controlunit 14 can include a visual indicator that indicates to a user that theliquid antifreeze 105 is being or has been injected and traversing themain water line 15 and subsequent lateral lines 22 a, 22 b, and 22 c.

In one aspect, the liquid antifreeze 105 is introduced from theantifreeze storage container 104 of the antifreeze supply unit 100 intothe main water line 15 via the one way injection port 46 at apredetermined pressure until the concentration of the liquid antifreeze105 required to protect the irrigation system 10 down to the minimumexpected air and/or ground temperature is reached. As discussed in moredetail below, the process of injecting the antifreeze solution 105 fromthe antifreeze storage container 104 of the antifreeze supply unit 100into the main water line 15 continues until the main line 15 and all thelateral lines (e.g., 22 a, 22 b, and 22 c) of the irrigation system 10have been treated with the liquid antifreeze 105.

With reference to FIGS. 1 and 8-10, one method of operation of theirrigation control system 10 will now be described. While reference willbe made to the winterization control unit 14 of FIG. 1, it is to beappreciated that this exemplary method of operation of the irrigationcontrol system 10 can be likewise controlled by any of the winterizationcontrol units 114, 214, 314, and 414.

With reference to FIG. 8, during the warm months when the air and groundtemperatures are well above freezing temperatures, the main irrigationcontroller 12 is in a normal operation mode, as in step 500. In step502, with the main irrigation controller 12 being in the normaloperation mode, the gate valve 19 is open, the control valve 40 is setto receive input from the water supply 18, and the main irrigationcontroller 12 is programmed to operate at normal flow rates in the mainline 15 and auxiliary lines 22 a, 22 b, and 22 c, and the winterizationcontrol unit 14 is in standby mode. With the winterization control unit14 being in standby mode, the winterization control unit 14 isprogrammed to permit normal irrigation operation controlled by the mainirrigation controller 12, as shown in step 504.

As discussed above and depicted at step 506, the winterization controlunit 14 receives ambient air temperature data and water temperature dataat predetermined intervals from the air temperature sensor 32 and thewater temperature sensor 36, respectively. At step 508, the processor 16of the winterization control unit 14 can access the historicaltemperature trends stored in the memory 20 and determine whether thetrend in the received air temperature readings is such that the airtemperature is likely to approach the predetermined low temperaturethreshold stored in the memory 20 of the winterization control unit 14.If the answer is “yes,” at step 510, the processor 16 of thewinterization control unit 14 determines whether the received watertemperature readings indicate a trend that the water temperature in themain water line 15 will remain above a minimum threshold temperature,for example, above a minimum threshold of 35° F. or 2° C. (in onespecific example, the threshold is 1.67° C.). It is understood that theminimum threshold is preferably near the freezing point of the liquidnormally present in the lines, e.g., with water, the minimum thresholdmay be a value within a range of between 1-7° C.

If the temperatures in the main water line 15 are determined by thewinterization control unit 14 to be below the predetermined minimumthreshold, at step 512, a temporary irrigation system shutdown isperformed where the winterization control unit 14 executes a temporaryirrigation system shutdown in step 514 after which steps 506 and 508 arerepeated. If the winterization control unit 14 determines at step 508that the air temperature is not at (or below) the predetermined lowtemperature threshold, the main irrigation controller 12 reverts back toits normal operation mode, shown by the arrow going from step 508 backto step 500 in FIG. 8.

If, however, the winterization control unit 14 determines, at step 508,that the air temperature is at or below the predetermined temperaturethreshold, and determines, at step 510, that the in-pipe watertemperature is at or below the predetermined low temperature threshold,the winterization control unit 14, at step 516, begins the execution ofan extended system shutdown for winter, otherwise known as winterizationcycle, or simply winterization. If the winterization control unit 14includes a visual indicator to alert the user that the winter shutdownhas been initialized, at step 518, the winterization control unit 14causes the visual indicator (e.g., an LED light) to be illuminated. Inanother approach, the visual indicator is a message on a display of thewinterization control unit 14, or an audible alarm signal.

At step 520, the processor 16 of the winterization control unit 14cross-references antifreeze concentration values associated with the zipcode where the winterization control unit 14 is located. In oneapproach, the antifreeze concentration values are preset by a user andstored in the memory 20 of the winterization control unit 14. Next, inone approach shown in step 522, the winterization control unit 14 sendsa signal (e.g., an electrical power signal or a data signal) that turnsoff electrical power to the main irrigation controller 12, shutting themain irrigation controller 12 down. For example, as shown in FIG. 4, theprocessor 216 of the winterization control unit 214 can send the signalto turn off electrical power to the main irrigation controller 212 viathe main power control switch 236 or from the input/output 224 of thewinterization control unit 214 directly to the input/output 221 of themain irrigation controller 212.

With the main irrigation controller 12 being shut down, at step 524, thewinterization control unit 14 sends a signal (e.g., an electrical powersignal or a data signal) to the control valve 40 via the connection line38 to switch input from the water supply 18 in the main water line 15 tothe liquid antifreeze 105 in the antifreeze concentrate delivery line44. At step 526, the winterization control unit 14 activates a selectedone of irrigation zones 22 a, 22 b, and 22 c coupled to the zone valves24 a, 24 b, and 24 c, respectively.

Then, at step 528, the winterization control unit 14 sends a signal thatcauses the pressure reducing valve 48 to assume a position adapted toprovide a predetermined flow rate desired for injecting the liquidantifreeze 105 from the antifreeze storage container 104 of theantifreeze supply unit 100 into the main water line 15. Finally, at step530, the winterization control unit 14 sends a signal to the antifreezesupply unit 100 via the connection 54 that causes the antifreeze supplyunit 100, and more specifically, the pump 106 of the antifreeze supplyunit 100, to dispense the liquid antifreeze 105 from the antifreezestorage container 104 of the antifreeze supply unit. The liquidantifreeze 105 is dispensed from the antifreeze storage container 104 ata flow rate and pressure directed by the signal received by theantifreeze supply unit 100 from the winterization control unit 14 intothe main water 14 until the predetermined concentration of the liquidantifreeze 105 in the main water line 15 and each irrigation zone 22 a,22 b, and 22 c is achieved.

In one approach, the signal from the winterization control unit 14 isgenerated by the processor 16 and sent via the connection 54 to a logiccircuitry located within the pump 106 of the antifreeze supply unit 100,with the logic circuitry being adapted to interpret this signal andinitiate the injection of the liquid antifreeze 105 from the antifreezestorage container 104 of the antifreeze supply unit 100 into the mainwater line 15. In another approach, the signal from the winterizationcontrol unit 14 is generated by the processor 16 and sent via theconnection 54 to a logic circuitry located away separate from the pump106, for example, on the housing 102 of the antifreeze supply unit 100,or to an electrical input directly coupled to the pump 106, orindirectly coupled to the pump 106 via the housing 102 of the antifreezesupply unit 100 or via another intermediate device.

In one aspect, flow in the main line 15 is controlled by an electronicproportioning valve (not shown) located upstream of the control valve 40and measured using the flow sensor 41. The flow sensor 41 can includecircuitry and a transmitter configured to transmit the flow ratesmeasured in the main water line 15 to the winterization control unit 14.The winterization control unit 14 is programmed to interpret theinformation received from the flow sensor 41 regarding the flow rate inthe main water line 15 to determine a desired pressure and operatingspeed of the pump 106 of the antifreeze supply unit 100 for introducingthe liquid antifreeze 105 from the antifreeze storage container 104 ofthe antifreeze supply unit 100 into the main water line 15.

With reference now to FIG. 9, in step 532, the flow sensor 41 measuresthe flow in the main water line 15 while the liquid antifreeze 105 isbeing injected into the main water line 15. If, at step 532, the flowsensor 41 transmits information to the winterization control unit 14that the flow in the main water line 15 is not as expected (e.g.,undesired fluctuations in the flow are present), the sequence returns tostep 528 where the pressure reducing valve 48 is reset to an appropriateposition to result in a desired flow rate. If, at step 532, the flowsensor 41 transmits information to the winterization control unit 14that the flow in the main water line 15 is as expected, at step 534, thepump 106 of the antifreeze supply unit 100 continues to deliver theliquid antifreeze 105 from the antifreeze storage container 104 of theantifreeze supply unit 100 into the main water line 15.

As the lateral zones 22 a, 22 b, and 22 c are sequentially activated andthe antifreeze solution 105 is introduced into them, a pressure readingsignal from the pressure sensor 28 attached to the main line 15 can besent to the winterization control unit 14 at step 536. When the pressurereading signal is received from the pressure sensor 28, at step 538, theprocessor 16 of the winterization control unit 14 interprets thispressure reading signal to determine whether the liquid antifreeze 105has reached the last spray head of a sprinkler (e.g., 25 c).

If the answer at step 538 is no, at step 540, the winterization controlunit 14 de-energizes the zone currently receiving the antifreezesolution 105 and activates the next zone in the sequence such that eachzone 22 a, 22 b, and 22 c of the system 10 is sequentially treated untilthe entire system 10 is filled with the antifreeze solution 105. If theanswer at step 538 is yes, the winterization control unit 14 sends asignal to the control valve 40 via the connection 38 to turn the watersupply off via the gate valve 19 at step 542.

With the control valve 40 being set to off with relation to the watersupply 18, and preferably, with the gate valve 19 being set to off, thezones 22 a, 22 b, 22 c and the pump 106 of the antifreeze supply unit100 are de-energized at step 544. As described above, when the desiredconcentration of the liquid antifreeze 105 is reached in the main waterline 15 and all lateral lines 22 a, 22 b, and 22 c (detectable by flowrate/line length calculation or a change in pressure from a change influid density being emitted from spray heads), the pump 106 of theantifreeze supply unit 100 can be deactivated (to stop the injection ofthe liquid antifreeze 105 into the irrigation system 10). Thisdeactivation of the pump 106 of the antifreeze supply unit 100 can beaccomplished via a signal sent from the winterization control unit 14 tothe antifreeze supply unit 100, or via a signal sent from a sensor(e.g., pressure sensor 28) to the antifreeze supply unit 100.

Also at step 544, pressure from the main line 15 is relieved through adrain port on the pressure reducing valve 48, and the control valve 40is set to antifreeze input. Then, at step 546, the winterization controlunit 14 is set to a lower power “sleep mode”, temperature protectionlimits are set, and the temperature trend monitoring mode is enabled,allowing the winterization control unit 14 to monitor the winterizationcycle operation of the system 10. The temperature protection limits canbe stored in the memory 20 of the winterization control unit 14 andrepresent a range of water temperatures (for example, +17° F. (20% byvolume propylene glycol); +4° F. (30% by volume propylene glycol), −13°F. (40% by volume propylene glycol), −28° F. (50% by volume propyleneglycol)) acceptable during the winterization cycle.

During the winterization cycle, the system 10 is preferably in atemperature monitoring, low power state designed to consume a minimalamount of power. This low power state includes both the winterizationcontrol unit 14 and the main irrigation controller 12. During thewinterization cycle, the winterization control unit 14 can, atpredetermined intervals, emerge from the sleep mode to receivetemperature readings of the air, water, and/or ground temperatures. Forexample, during the winterization cycle, the air temperature sensor 32and the water temperature sensor 36 can measure air and watertemperatures, respectively, at predetermined intervals, and send signalscontaining air temperature and water temperature data to thewinterization control unit 14.

Using the data received from the sensors 32 and/or 36, the temperaturetrending algorithm programmed into its processor 16, and optionally, thehistorical temperature data stored in its memory 20, at step 548, thewinterization control unit 14 determines if the temperature of theirrigation system 10 is stable or appearing to migrate toward a warmtemperature where freezing is no longer an issue, or a temperature belowwhich the system 10 is no longer protected by the particularconcentration of the liquid antifreeze 105 injected into the system 10during the first winterization cycle. If the answer at step 548 is yes,in other words, if the processor 16 predicts that the temperatures arelikely to approach one of the pre-defined upper and lower limits, thewinterization control unit 14 determines whether the air and/or watertemperature is expected to exceed the upper trend limit or the lowertrend limit at step 550.

If the temperature trend is predicted by the processor 16 of thewinterization unit 14 to drop below the temperature determined to be theminimum acceptable temperature based on the amount of liquid antifreeze105 injected into the system 10, the winterization control unit 14 willconduct a partial system power up and begin an immediate purge of themain line 15 and the lateral lines 22 a, 22 b, and 22 c, similar insequence to the first winterization cycle (steps 518-530), using ahigher concentration of the liquid antifreeze 105 necessary to obtain anincreased level of protection against freezing (for example, 20% byvolume propylene glycol freezes at +17° F.; 30% by volume propyleneglycol freezes at +4° F.; 40% by volume propylene glycol freezes at −13°F.; and 50% by volume propylene glycol freezes at −28° F.). In thiscase, at step 552, the processor 16 of the winterization control unit 14recalculates the expected minimum temperature of the system 10 anddetermines the liquid antifreeze 105 concentration necessary tosufficiently prevent the system 10 from freezing.

Then, referring again to FIG. 8, at step 554, the pump 106 of theantifreeze supply unit 100 is again prepared for dispensing while thesequence returns to step 518, the winter shutdown activation LED lightagain turns on to indicate that the winterization process is activated,and additional “winterization” of the system 10 is performed in steps520-544 to supply liquid antifreeze 105 from the antifreeze supply unit100, in the amount determined by the winterization control unit 14 atstep 552, to the system 10. In one approach, the system 10 canaccommodate at least two winterization cycles per season to accommodatefor unexpected temperature drops. It is to be appreciated that thesystem 10 can alternatively be adapted to accommodate at least three,four or more winterization cycles per season in areas where majortemperature fluctuations and downswings are common.

With reference back to FIG. 9, if at step 550, the winterization controlunit 14 determines that the temperature readings received from the airtemperature sensor 32 and/or the water temperature sensor 36 indicate anincreasing trend expected to exceed the upper threshold temperature,then, at step 556, the winterization control unit 14 determines whetherthe observed upper temperature trend correlates with the system start-upcalendar date stored in the memory 20 of the winterization control unit14. If the answer at step 556 is no, the winterization control unit 14returns to its sleep mode and steps 546 through 556 are repeated atpredetermined intervals (e.g., twice daily, once daily, every other day,twice a week, once a week) until the winterization control unit 14determines in step 556 that the upper temperature trend correlates withthe stored calendar date for system start-up. As described above, atthis time, or at any other time determined by a user such as a homeowneror a contractor, the stored temperature trend indications and calendardates (e.g., stored based on manual user input or selection) can beoverridden to initiate system start-up by a manual input at the physicallocation of the winterization control unit, from a central station, orfrom a mobile central controller.

The processor 16 of the winterization control unit 14 is programmed toexecute a system start-up, which can start with the gate valve 19controlling the water supply 18 being turned back on at step 558. Next,in step 560, the winterization control unit 14 indicates that the normalirrigation operation mode has been turned on. The winterization controlunit 14 can include a visual indicator in the form of an LED light or anon-screen message that indicates whether the normal irrigation mode ison or off.

The system start-up is preferably performed such that the liquidantifreeze 105 is purged from the system 10 slowly at reduced pressuresto avoid aspiration of the liquid antifreeze 105 into the surroundingair. Referring to FIG. 10, in step 562, the winterization control unit14 maintains the control valve 40 at the setting for input of the liquidantifreeze 105 and sets the pressure reducing valve 48 to allow lowpressure bleeding of zones 22 a, 22 b, and 22 c. To that end, in step564, the winterization control unit 14 activates a selected zone 22 aand in step 566, sends a signal that causes the antifreeze solution tobe flushed from the selected zone 22 a.

While the antifreeze solution is being flushed from the system 10, thewinterization control unit 14 is programmed to determine whether apressure signal has been received from the pressure sensor 28. If atstep 568, the winterization control unit 14 determines that the pressuresignal has not yet been received from the pressure sensor 28, thewinterization control unit 14 continues to flush the liquid antifreeze105 from the selected zone 22 a (as indicated by the arrow looping backfrom step 568 to step 566). If, on the other hand, the winterizationcontrol unit 14 determines at step 568 that the pressure signal has beenreceived from the pressure sensor 28, the winterization control unit 14sends a signal that causes the pressure reducing valve 48 to fully openand to run the selected zone 22 a for a predetermined period of time,for example, 30 seconds. It will be understood that 30 seconds has beenselected by way of example only, and that any other suitable timeinterval can be used, for example, 20 seconds, 45 seconds, one minute, 2minutes, or more.

In step 572, the flow sensor 41 measures the flow in the selected zone22 a and determines whether the flow is as expected by checking themeasured flow rate against flow rate values stored in the memory 20 ofthe winterization control unit 14. If the flow sensor 41 sendsinformation to the winterization control unit 14 that the flow in theselected zone 22 a is not as expected (e.g., unexpected flowfluctuations are present), or if a leak in the main line 15 is detected,the winterization control unit 14 is programmed to send a signal (e.g.,a power signal or a data signal) that shuts down the system 10 in step574. In one approach, the winterization control unit 14 includes anaudible alarm that indicates that the flow rate is too high or too low.Then, at step 576, the winterization control unit 14 remains in shutdownmode until an input is received from the user that the zone where theflow rate was too low or too high, or where the leak was detected, hasbeen repaired. Once such an input or signal indicating that repair hasbeen completed is received at step 576, the winterization control unit14 proceeds to flush the antifreeze solution from the remaining zones assteps 566-572 are repeated.

If, in step 572, the flow sensor 41 sends information to thewinterization control unit 14 that the flow in the selected zone 22 a isas expected, the winterization control unit 14 continues to cause theantifreeze solution to be purged from the selected zone 22 a. Thelateral zones 22 a, 22 b, and 22 c are preferably purged sequentially.At step 578, a pressure reading signal from the pressure sensor 28attached to the main line 15 is sent to the winterization control unit14. When this signal is received from the pressure sensor 28, theprocessor 16 of the winterization control unit 14 interprets it todetermine whether the last zone has been purged of the antifreezesolution. If the winterization control unit 14 determines, based on thereceived pressure signal, that not all zones have been purged yet, thewinterization control unit 14 proceeds to flush the antifreeze solutionfrom an appropriate zone and the steps 566-578 are repeated. If, on theother hand, the winterization control unit 14 determines that all zoneshave been purged, the winterization control unit 14 proceeds torelinquish control of the irrigation system 10 to the main irrigationcontroller 12 and enters standby mode until the next winterizationcycle.

With reference to FIG. 11, an exemplary method for controlling theirrigation system will now be described. For exemplary purposes, themethod is described in the context of the system of FIG. 1, but it isunderstood that embodiments of the method may be implemented in this orother systems. The method includes outputting a signal (e.g., via theconnection 54) from the winterization control unit (e.g., winterizationcontrol unit 14 of the irrigation system 10) (step 608). As discussedabove, in some embodiments, the irrigation system 10 includes a waterline 15 and an antifreeze supply unit 100 coupled to the water line 15(for example, via the connection 44 and through the one way inlet port46). The antifreeze supply unit 100 includes an antifreeze storagecontainer 104 that contains the liquid antifreeze 105. The winterizationcontrol unit comprises a processor 16 and a memory 20 (e.g., that storestemperature data and instructions executable by the processor 16).

In one approach depicted in step 602, the outputting of the signal bythe winterization control unit in step 608 can be in response toreceiving, at the winterization control unit, at least one of air andwater temperature data from at least one sensor, for example one or moreof sensors (e.g., sensors 28, 32, 36). In one approach shown in step604, the outputting of the signal by the winterization control unit instep 608 can be in response to a determination, at the winterizationcontrol unit, that the air and/or water temperatures received from thetemperature sensors (e.g., sensors 32 and/or 36) are exhibiting a trendthat is approaching a predetermined temperature threshold. Thepredetermined temperature threshold can be, for example, a minimumacceptable temperature for the system to be in normal irrigationoperation. As described above, the minimum acceptable temperature can bestored in the memory of the winterization control unit.

In another approach depicted in step 606, the outputting of the signalby the winterization control unit in step 608 can be in response toreceiving a manual user input, for example, a command to initialize thewinterization cycle. As described above, the user input to initializethe winterization cycle can be provided at the location of thewinterization control unit (e.g., by manual manipulation of the userinterface 228) or via a wired or wireless connection from a remotelocation such a central station or a central controller. In a variationof step 606, the manual user input resulting the outputting of thesignal by the winterization control unit in step 608 can be a calendardate (triggering the start-up of the winterization) previously enteredor selected through manual user input by the user into the winterizationcontrol unit 14, where the reaching of the stored calendar date triggersthe outputting of the signal.

In some embodiments, steps 602 and 604 and/or 606 and/or variations canbe considered to result in a generic step of determining by thewinterization control unit that winterization of the irrigation systemis to be initiated (activated) or deactivated, which then leads to theperformance of step 608.

In step 610, the signal that is output by the winterization control unitin step 608 is received at the antifreeze supply unit (e.g., antifreezesupply unit 100). As discussed above, the signal sent by thewinterization control unit to the antifreeze supply unit can be anelectrical signal (e.g., an A/C power signal) and/or a data signal thatis sent via a wired connection or wirelessly. In one approach, theantifreeze supply unit can include logic circuitry adapted to interpretthe signal received from the winterization control unit. For example,such logic circuitry can be implemented into or coupled to a pump (e.g.,pump 106) that forms a part of the antifreeze supply unit and which iscoupled to the antifreeze storage container (e.g., container 104).

Next, the method includes injecting, responsive to the signal, at leastsome of the liquid antifreeze 105 from the antifreeze storage container104 of the antifreeze supply unit 100 into the water line (e.g., waterline 15) (step 612). As discussed above, the injecting step 612 mayinclude activating the pump (e.g., pump 106) of the antifreeze supplyunit 100 to initiate the injection of the liquid antifreeze 105 from theantifreeze storage container 104 via a connection (e.g., connection 44)into the main water line 15. In one approach, the antifreeze supply unit100 may lack the pump 106 and the antifreeze storage container 104 ofthe antifreeze supply unit 100 may be a pressurized container that caninject the antifreeze solution 105 into the connection 44 and the mainwater line 15 when a valve (not shown) coupled to the pressurizedcontainer is opened in response to the signal (e.g., a power signaland/or a data signal) received at the antifreeze supply unit 100 fromthe winterization control unit 114. Some embodiments of the exemplaryautomatic irrigation freeze protection system 10 described above haveadvantages over currently known systems at least because they eliminatethe need for homeowners to schedule winterization service calls and savethe homeowners operation costs and aggravation of being dependent on theavailability of a service person to winterize their irrigation systemsshould the need arise.

As described above, in some embodiments, the winterization control unit114 outputs an additional signal to terminate the injection of theliquid antifreeze 105 into the main line 15. For example, in some cases,the liquid antifreeze 105 is injected for a specific length of time oruntil a certain pressure in the main line 15 is obtained. In someembodiments, an output from the winterization control unit 114 is notneeded in order to terminate the injection. For example, the antifreezesupply unit (e.g., unit 100) is configured to inject antifreeze solutionfor a predefined length of time.

By eliminating the need to schedule a winterization service call with anirrigation system contractor, the homeowner or the light commercialproperty owner is assured that the automatic irrigation system 10 isbeing winterized at the optimal time each and every year without havingto be concerned whether the system 10 has been exposed to extreme coldtemperatures which could have resulted in freeze damage to the system10. In addition, the system 10 utilizes a much safer and effective meansof providing freeze protection to the automatic irrigation system bywinterizing and spring actuation of the system at lower pressures andflow rates.

While the invention herein disclosed has been described by means ofspecific embodiments, examples and applications thereof, numerousmodifications and variations could be made thereto by those skilled inthe art without departing from the scope of the invention set forth inthe claims.

What is claimed is:
 1. An irrigation system comprising: an antifreezesupply unit coupled to a water line of the irrigation system, theantifreeze supply unit including a storage container containing a liquidantifreeze; and a control unit in communication with the antifreezesupply unit, the control unit being configured to send a signal to theantifreeze supply unit and the antifreeze supply unit being configuredto inject at least some of the liquid antifreeze from the antifreezestorage container into the water line in response to receiving thesignal from the control unit.
 2. The system of claim 1, furthercomprising a pump configured to inject at least some of the liquidantifreeze into the water line, the pump being housed at least in partwithin the antifreeze supply unit.
 3. The system of claim 1, wherein thecontrol unit includes a visible status indicator indicating whether theliquid antifreeze has been injected into the water line.
 4. The systemof claim 1, further comprising an injection port positioned between theantifreeze supply unit and the water line, the injection port includingone of a one-way injection valve and a check valve.
 5. The system ofclaim 1, further comprising a pressure reducing valve coupled to andpositioned between the antifreeze supply unit and the water line, thepressure reducing valve being configured to control a pressure and aflow rate of the liquid antifreeze during winterization.
 6. The systemof claim 1, further comprising a control valve coupled to the waterline, the control unit, and the antifreeze supply unit, the controlvalve being configured to any one of permit and restrict flow of atleast one of water and the liquid antifreeze through the water line. 7.The system of claim 1, wherein the control unit is configured toinitiate injection, from the antifreeze supply unit, of at least some ofthe liquid antifreeze into the water line at a concentration based on atleast one of temperature values stored in the control unit, watertemperature data received by the control unit from at least one watertemperature sensor, air temperature data received by the control unitfrom at least one air temperature sensor, and manual user input.
 8. Thesystem of claim 1, further comprising at least one of a temperaturesensor, pressure sensor, and flow sensor coupled to the water line andthe control unit, the temperature sensor being configured to send to thecontrol unit temperature data for at least one of water in the waterline and ambient air, the pressure sensor being configured to send tothe control unit pressure data for at least one of water and the liquidantifreeze in the water line, and the flow sensor being configured tosend to the control unit flow rate data of at least one of water and theliquid antifreeze in the water line.
 9. The system of claim 1, whereinthe control unit is programmed to include at least one temperature trendhaving a lower threshold based on a geographical location of the controlunit.
 10. The system of claim 1, further comprising an indicator coupledto the water line and configured to measure flow in the water line, andprovide a signal when the flow in the water line fluctuates, the signalbeing at least one of a visible signal, an audible signal, a display ona screen, and a wireless signal.
 11. A control unit for controlling anirrigation system comprising: a memory storing temperature thresholds ofat least one of air and water temperatures associated with ageographical location of the irrigation system, the memory including atleast a lower temperature threshold; an output configured to be incommunication with an antifreeze supply unit including an antifreezestorage container coupled to a water line of the irrigation system; anda processor coupled to the memory and the output; wherein the processoris configured to generate a signal at the output upon a determination bythe processor that at least one of air and water temperature approachesthe lower temperature threshold, the signal being configured to causethe antifreeze supply unit to inject at least some of the liquidantifreeze from the antifreeze storage container into the water line.12. The control unit of claim 11, wherein the processor of the controlunit is configured to generate the signal in response to a manual userinput.
 13. The control unit of claim 11, wherein the control unitconfigured to receive at least one of air temperature and watertemperature data from at least one sensor coupled to at least one of thecontrol unit and the water line.
 14. The control unit of claim 11,wherein the memory includes an upper temperature threshold and theprocessor is configured to provide a signal at the output upon adetermination by the processor that at least one of air and watertemperature approaches the upper temperature threshold, the signalconfigured to cause the liquid antifreeze to be at least in part purgedfrom the water line.
 15. The control unit of claim 14, wherein thememory of the control unit stores historical values of the at least oneof the air and water temperatures associated with the geographicallocation of the irrigation system, the processor being configured toanalyze, in view of the stored historical values, the at least one ofthe air temperature data and water temperature data received from the atleast one sensor.
 16. The control unit of claim 11, wherein the controlunit forms a part of a main irrigation controller that controls flowthrough the water line.
 17. The control unit of claim 11, wherein thecontrol unit is configured to be removably coupled to a main irrigationcontroller that controls flow through the water line.
 18. The controlunit of claim 11, wherein the processor of the control unit isconfigured to provide a signal at the output to one of start andinterrupt at least one of a supply of water into the water line and aninjection by the antifreeze supply unit of the liquid antifreeze intothe water line.
 19. The control unit of claim 11, wherein the processorof the control unit is configured to generate a signal at the output tocontrol flow rate of injection by the antifreeze supply unit of theliquid antifreeze into the water line.
 20. The control unit of claim 11,wherein the control unit includes a visible status indicator indicatingwhether the liquid antifreeze has been injected into the water line. 21.A method for controlling an irrigation system comprising: outputting asignal from a control unit of an irrigation system comprising a waterline and an antifreeze supply unit coupled to the water line andincluding an antifreeze storage container containing a liquidantifreeze, wherein the control unit comprises a processor and memorycontaining instructions executable by the processor; receiving thesignal at the antifreeze supply unit; and injecting, responsive to thesignal received at the antifreeze supply unit, at least some of theliquid antifreeze from the antifreeze storage container of theantifreeze supply unit into the water line.
 22. The method of claim 21,further comprising receiving, at the control unit, at least one of airand water temperature data from at least one sensor unit.
 23. The methodof claim 21, wherein the outputting the signal is responsive to manualuser input.
 24. The method of claim 21, wherein the antifreeze supplyunit includes a pump coupled to the antifreeze storage container andwherein the injecting the at least some of the liquid antifreeze furthercomprises initiating the pump.
 25. The method of claim 24, wherein theinjecting at least some of the liquid antifreeze further comprises thecontrol unit receiving flow rate data from at least one flow ratesensor, and controlling, via the processor of the control unit, speed ofthe pump based on the flow rate data received from the at least one flowrate sensor.
 26. The method of claim 21, wherein the injecting at leastsome of the liquid antifreeze further comprises the control unitreceiving pressure data from a pressure sensor coupled to the waterline, and interrupting the injecting of the liquid antifreeze into thewater line responsive to the pressure data received from the pressuresensor.
 27. The method of claim 21, further comprising programming thecontrol unit with at least one historical temperature trend having anupper threshold and a lower threshold based on a geographical locationof the control unit.
 28. The method of claim 21, further comprisingoutputting from the control unit, at least one of a signal thatinterrupts flow of at least one of water and the liquid antifreezethrough the water line, and a signal to purge at least some of theliquid antifreeze from the water line.
 29. The method of claim 28,wherein the signal to purge at least some of the liquid antifreeze fromthe water line is responsive to one of manual user input and temperaturedata received by the control unit from at least one temperature sensor.30. The method of claim 21, further comprising generating via at leastone temperature sensor at least one of water and air temperature dataafter the injecting at least some of the liquid antifreeze from theantifreeze storage container of the antifreeze supply unit into thewater line, and causing the antifreeze storage container of theantifreeze supply unit to inject additional liquid antifreeze into thewater line responsive to the temperature data received by the controlunit from the at least one temperature sensor.